Motorola R2550 Service Manual

acquired, 
the Freq: 
field in 
the  RF 
Control
zone  indicates  metering 
and its 
counterpart  in
the  meter  zone 
displays  the 
channel  on which
the  canier  was 
detected.  Also 
displayed  in 
the
meter  zone 
are the preset 
number  of the channel,
the  received  power 
level and the 
modulation
level  of the  received  signal.
To  activate  the Preset 
Scan function, 
depress the
Preset  Scan  softkey. This  key  not 
only  begins
the  preset 
scanning  but also 
seryes  as  a contin-
ue  key...

3-7.I.3 
AC/DC VOLTMETER
The  Analyzer  provides 
a general 
purpose
AC/DC  digital voltmeter  (figure 
3-12).  The
voltmeter  input 
is the  same  front panel 
BNC
port  that also 
serves  as 
the  input 
for the
SINAD/DIST  meter, 
the VERT 
oscilloscope
input,  and the period 
COUNTER  IN.
Move  the  cursor  to 
the  Range: 
field. Select
the  voltage  range (1V, 
10V, or 100V 
DC) by
pressing  the  applicable  softkey. 
Maximum  AC
range  is 
70  VAC.  If 
ttre  optional 
battery pack 
is
installed,...

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RF
DISPTRY PFESET
steil...

PLIPER 
Counter
This  softkey  provides 
a convenient  means 
of
measuring  the frequency 
of Motorola
Private-Line  (PL) 
or any  other  low frequency
audio  tones 
with 3 
digit  resolution. 
Period
measurement  makes 
it possible 
to measurs  low
frequencies  down to high  resolution  without
the  need  for the  long  gate 
times  associated
with  frequency 
counting.
CAUTION
Do  not 
input 
frequencies  above 
400
kHz  to 
the  period 
counter.  Slow 
down
of  system  operations  will 
result.
DPL...

(dBm) 
graph. 
Either the ANT 
or RF 
VO  port
may  be 
selected  for 
input  from 
the RF 
Con-
trol:  zone.  The 
amount  of input 
attenuation
may  also be selected  within 
the zone 
to 
vary
the  sensitivity  of 
the  Spectrum  Analyzer.
NOTE
If  SPECTRIIM  ANALYZER 
is 
selectedwhile
the  Preset 
Scan 
feature  is 
active,  the 
spec-
trum  analyzer  wiII 
be temporarily  disabled
during  scanning,  but 
will 
become  active
again  when 
the analyzer  loclcs 
onto a 
signal.
Sensitivity The  SA...

NOTE
Because  the 
R-2550  Analyzer 
has 
a 
fiilly
digital  oscilloscope  (storage 
scope), 
-it inher-
titty  lrot 
some  characteristics  which 
are
dffirent  from the 
real-time  analog 
scopes
\i*ttto,  to 
most  users.  For 
best  overall
-results, 
it is  recommended  that 
the trigger
Ievel  be 
set  to 
500  and 
the triggering  be 
set
to  AUTO.
The  Display  area 
of 
the  screen  will indicate
rr,roouiniroN  scoPE 
with 
the input  signal
displayed  in 
a time-versus-frequency  graph 
To...

Horizontal 
Position
Adjust  the horizontal  position 
through the
(<  >)  cursor  field 
either  by using  the 
desired
softkey  (MovE 
LEFT, MOVE  RIGHT) 
or by
using  the rotary 
TUNING  knob.
Vertical  Sensitivity
Press  ttre  desired softkey  to 
select the  Vertical
Sensitivity  (AM: 
|Vo, lo 50Vo  p$ 
division,
FM:  100 Hzto 
50 kHz  per 
division,  dependent
on  bandwidth  selected).  When 
all ranges
cannot  be shown  on 
one  screen,  press 
the
more  softkey  for 
additional  selections.
NOTE...

3.8 
OTHER  FUNCTIONS
3-8.1  Audio  Monitor
The  Analyzer  has 
a 
speaker  for 
the  purpose 
of
audibly  monitoring 
the 
recovered  baseband
signal  in 
the  MONITOR  and 
DUPLEX  modes
and  the modulating  signal in 
the 
GENERATE
mode.  Switching  between 
the 
two  is 
automatic.
Using  the 
VOLUME  control, the 
input  signal  to
the  speaker  is 
adjustable  to 
a maximum  level 
of
0.5  watts  rms.
The  speaker  is 
also  used  for 
audible  warnings,
such  as RF 
overtemperature.
3-8.2  Remote...

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SPFs il  i 
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Figure  3-15.  Special Functions  Menu
of all  special  functions  to 
the  factory  standard  .I{VM 
Clear
state.  This 
will 
switch  all 
decoding  to 
internal.  This 
softkey  erases the entire  RF Preset  -
memory  area and  front panel 
CAL memory.
SYSTEM  FUNCTIONS  The Analyzer 
must...

ENABLE/DISABLE 
Auto 
Switch  to 
MON  if
0.1  W
Allows  the 
unit  to 
automatically  switch 
to
the  MOMTOR  mode 
when 
Power  levels
greater  than 0.1 watt  are applied  to 
the  RF
IN/OUT  front 
Panel  connector
INTERNAL/EXTERNAL  INPUT 
Decoding
Switches  the 
decoder  function 
between the
internal  monitor 
demodulated  signal 
and 
the
signal  at 
the  VERT/SINAD  front 
panel 
con-
nector.
3-8.4.1  Special Function 
Selection
To  select  a 
special  function 
follow 
the following
procedure....